Xanthate esters



United States Patent 3,155,701 XANTHATE ESTERS Martin Hauser, Stamford, Conn, and Norbert M. Bilrales, Livingston, N..l., assignors to American Cyanarnid Qornpany, tamord, 601111., a corporation of Maine No Drawing. Filed Dec. 26, 1962, Ser. No. 247,275 7 Gimme. (til. 260-455) This invention relates to, and has for its object, the provision of a new class of compounds. More particularly, it relates to a class of xanthates which can be prepared by the novel reaction between a metal salt of an O-xanthic ester and a halo-derivative of mesityl oxide. It further relates to a class of compounds, the members of which are useful as promoters in the beneficiation of ore-s by froth flotation. It relates still further to a class of compounds which have biocidal properties.

Other aspects will be apparent from the following detailed description in conjunction with examples showing embodiments of the present invention.

The xanthates of the present invention may be represented by the following general formulae:

wherein X and Y are hydrogen or halogen (e.g., chloro, brorno or iodo), and R is an alkyl or aralkyl group. Alkyl groups may contain up to twelve carbons and may be substituted with one or more (e.g., up to about three) electronegative groups such as halogen (e.g., chloro, bromo and fluoro), nitro, cyano or lower alkox groups. Aralkyl groups may be monocyclicflower alkyl) or bicyclicflower alkyl) groups having up to about three halo (e.g., fiuoro, chloro or bromo), lower alkyl, cyano, lower alkoxy or nitro radicals.

Compounds of Formula I and Formula II are prepared by the reaction or" a halo derivative of mesityl oxide with a metal salt of an O-xanthic acid ester, the reactions being represented by the following equations:

wherein M is an alkali metal (e.g., potassium or sodium), R, X and Y are as defined above, and HALO is chloro, bromo or iodo. conducted by contacting the reactants at moderate or reduced temperatures (e.g., between and 40 C.). Proportions are not critical and equimolar amounts of both, or an excess or" the halo-derivative of mesityl oxide may be used. The reaction can best be carried out in a diluent medium such as an inert polar organic solvent typified by acetone or dimethylformamide. The desired product remains in solution and the salt separates as a precipitate. If desired, the product may be purified by conventional washing techniques.

The term halo-derivatives of mesityl oxide as used herein embraces both addition and replacement products of mesityl oxide, both of which are known to the art. Mesityl oxide, a compound or" the Formula Ill:

(CH C=CHCO-CH can be hydrohalogenated (an addition reaction) or else The reaction may be advantageously halogenated either by a replacement reaction or an addition reaction. In the former case, the olefinic unsaturation in the starting material is retained. In the latter case, it is not. The halo-derivatives are of the following four types:

Specific members of this type of halo-derivatives of mesityl oxide will be shown in the' later-presented specific examples.

Among the alkali metal Xanthates which can be named as suitable for reaction with the halo-derivatives of mesityl oxide are the sodium and potassium salts of the following O-xanthates:

Compounds of Formula I and Formula II have valuable froth flotation promoting properties, and can be used in conventional flotation operations for the recovery of copper and zinc from sulfide ores containing these metals.

The following examples are presented to further illustrate the present invention. Parts are by weight unless otherwise specified.

EXAMPLE 1 S [2- 2 -M ethyl-3 -Br0m o-4-Ox0pentyl Ethyl X anthate A mixture of potassium ethyl xanthate (16' parts), 3,4-dioromo-4-methyl-2-pentanone (25.8 parts) and acetone (100 parts) was stirred for 16 hours at 25. The solution was filtered and freed. of acetone at reduced pressure. The residue was dissolved in ether (100 parts) and filtered. The ether was removed at reduced pressure. The residual product, S-[2-(2-methyl-3-bromo-4-oxopentyl)] ethyl xanthate, 16 parts yield), was a clear, dark-brown liquid.

EXAMPLE 2 S- [2-(2-Methyl-3-Cltloro4-Oxopeniyl)] Ethyl X anthate The procedure of Example 1 was employed using potassium ethyl xanthate and 3,4-dichloro-4-metl1yl-2-pentanone. A 35% yield of S-[Z-(2-methyl-3-chloro-4-oxopentyl)] ethyl xanthate was obtained. The product was a dark-brown liquid.

EXAMPLE 3 S- [2-(2-Methyl-3-Br0m0-4-Oxopcntyl)] Isopropyl Xanthate The procedure of Example 1 was employed using sodium isopropyl xanthate and 3,4-dibromo-4-methyl-2- pentanone. The residual product, S-[2-(2-methyl-3- bromo-4-oxopentyl)] isopropyl xanthate (67% yield), was an amber-colored liquid.

EXAMPLE 4 S- [2-(Z-Methyl-S-Chl0r0-4-Ox0pentyl)] Sec-Buzyl X anthate The procedure of Example 1 was employed using potassium sec-butyl xanthate and 3,4-dibromo-4-methyl- 2-pentanone. A 64% yield of S-[2-(2-methyl-3-chloro- 4-oxopentyl)] sec-butyl xanthate was obtained. The product was a dark-red liquid.

none. There was obtained a 77% yield of S-[Z-(Z-methyl- 3-iodo-4-oxopentyl)] ethyl xanthate, a dark-brown liquid.

EXAMPLE 6 S-[2-(Z-Methyl-3-Br0m0-4-Ox0pelztyI)] Amyl Xanthate The procedure of Example 1 was repeated using potassium amyl xanthate and 3-bromo-4-ehloro-4-methyl- Z-pentanone. The product, S-[2-(2-methyi-3-bromo-4- oxopentyl)] amyl xanthate (50% yield), was a darkbrown liquid.

EXAMPLE 7 S-[3-(2-Melhyl-4-Ox0-2-Pentenyl)] Ethyl Xaizthate Potassium ethyl xanthate (8.8 parts), 2-methyl-3- bromo-4-oxo-2-pentene (9.8 parts) and acetone (75 parts) were stirred hours at then refluxed for 2 hours. The mixture was filtered, acetone was stripped at reduced pressure and the residue was dissolved in ether (200 parts). The ethereal solution was filtered and the ether then stripped at reduced pressure. The residual product, S-[3-(2-methyl-4-oxo-2- entenyl)] ethyl xanthate (14.1 parts, 84% yield), was an amber-colored liquid.

EXAMPLE 8 S-[3-(Z-MeIhyl4-Oxo-2-Pentenyl)] Ethyl Xanthate The procedure of Example 7 was employed using potassium ethyl xanthate and 2-rnethyl-3-chloro-4-oxo- Z-pentene. There was obtained a 72% yield of an amber liquid identical to that in Example 7.

potassium sec-butyl xanthate and 2-methyl-3-bromo-4- xo-2-propene. The residual product, S-[3-(2-methyl- 4-oxo'2-pentenyl)] sec-butyl xanthate (75% yield), was

a dark-brown liquid.

EXAMPLE l1 S-[2-(2-MethyI-4-Ox0pentyl)] Ethyl Xanthate Potassium ethyl xanthate (16 parts), 4-bromo-4-rnethyl- Z-pentanone (17.9 parts) and acetone (150 parts) were stirred 16 hours at 25. The mixture was filtered and acetone was stripped at reduced pressure. The residue was dissolved in ether (100 parts) and filtered. The ether was stripped at reduced pressure leaving as residue 6.1 parts (28% yield) of a dark-brown liquid, S-[2-(2-methyl- 4-oxopentyl)] ethyl xanthate.

EXAMPLE 12 S- [2-(2-Methyl-4-Oxopentyl) ]Ethyl Xanthate The procedure of Example 11 was employed using potassium ethyl xanthate and 4-chloro-4-methyl-2-pentanone. There was obtained a 21% yield of a dark-brown liquid identical with that in Example 11.

4 EXAMPLE 13 S-[2-(2-Methyl-4-Ox0pentyl)] Ethyl Xanthate The procedure of Example 11 was employed using sodium ethyl xanthate and 4-bromo-4-methyl-2-pcntanone. There was obtained 24% of a dark-brown liquid identical with that in Examples 11 and 12.

EXAMPLE 14 S-[2-(2-Methyl-4-Ox0pcntyl)1 Isopropyl Xanthule The procedure of Example 11 was employed using potassium isopropyl xanthate and 4-bromo-4-methyl-2- pentanone. The residual product, S-[2-(2-rnethyl-4-oxopentyl)] isopropyl xanthate (17% yield), was an amber liquid.

EXAMPLE l5 S-{2(2-li4ethyl-4-Oxopei1tyl)] Amyl Xanthate The procedure of Example 11 was employed using potassium amyl xanthate and 4-bromo-4-methyl-2-pentanone. There was obtained a 31% yield of S-[Z-(Z-methyl- 4-oxopentyl)] amyl xanthate, a dark-brown liquid.

EXAMPLE l6 S-[2-(2-Methyl-3,3-Dichl0r0-4-Ox0pentyl)] Ethyl Xanthate Potassium ethyl xanthate (4 parts), 3,4,4-trichloro-4- methyl-Z-pentanone (5.1 parts) and acetone (50 parts) were stirred 16 hours at 25. The mixture was filtered and the acetone was stripped at reduced pressure. The residue was dissolved in ether parts) and filtered. The ether was stripped at reduced pressure. The residual product, S-[2-(2-methyl-3,3-dichloro-4-oxopentyl)] ethyl xanthate (4.3 parts, 60% yield), was a darlered liquid.

EXAMPLE 17 S-[Z-(Z-metlzyl-3-br0m0-3-iodo-4-oxopehtyl)] ethyl xanthate The procedure of Example 16 was employed using sodium ethyl xanthate and 3,4-diodo-3-bromo-4-mcthyl-2- pentanone. There was obtained a 50% yied of a darkbrown liquid, S-[Z-(2-methyl-3-bromo-3-i0do-4-oxopentyl)] ethyl xanthate.

EXAMPLE 18 S [2-(Z-Miethyl-3-Br0m0-4-Oxopentyl ]-Dodccylxanthate Following the procedure of Example 1, except for the use of sodium dodecyl xanthate instead of the xanthate starting material used therein, the product is obtained.

EXAMPLE 19 S- [2-(Z-Methyl-3-Chloro-4-Oxopentyl) Nitromerhylxanthate 7 Reaction of potassium nitromethyl xanthate and 3,4- dichloroA-methyl-Z-pentanone in accordance with the procedure of Example 1 leads to the compound S-[Z-methyl- 3-chloro-4-oxopentyl)]-nitromethyl xanthate.

EXAMPLE 20 S- [2-(Z-Melhyl-S-Bromo4-Oxopclltyl) Cyanoethyl Xanthate Following the procedure of Example 1, except tor the use of sodium cyanoethyl xanthate instead of the xanthate used therein, the product is obtained.

EXAMPLE 21 S-[2-(2-Melhyl-3-Chl0r0-4'0x0pentyl)] Benzyl Xmzlhutc Reaction of potassium benzyl xanthate and 3,4-dichloro- 4-methyl2-pentanone in accordance with the procedure of Example 1 leads to the compound, S-[2-(2-methyl-3- chloro-4-oxopentenyl)] benzyl xanthate.

EXAMPLE 22 S-[3-(2-Methyl-4-0xo-2-Pelztenyl)] Phenethyl Xanthate Replacement of the xanthate used in Example 1 with potassium phenethyl Xanthate leads to the product, S-[S- (2-methyl-4-oxo-Z-pentenyl)] phenethyl Xanthate.

EXAMPLE 23 Flotation a Copper Ore In order to show the utility of the xanthates of the present invention as flotation promoters, the xanthates of Examples 2, 7 and 11 were employed in the recovery of copper from the western United States, using the following procedure. The ore sample was ground for minutes at 60% solids with 0.06 1b./ton of promoter and 3.0 lbs/ton of ore, of lime (pH 9.5). It was then conditioned at 22% solids for one minute with 0.09 lb./ton of cresylic acid and 0.025 lb./ton of fuel oil. The pulp was floated for 8 minutes and the tailing analyzed for residual copper, with the following results.

Comparison was made with a conventional flotation reagent, allyl amyl Xanthate.

TABLE I Percent 011 in Compound Tailing S-[2-(2-methyl-3-ehloro-4-oxopentyl)] ethyl xanthate" S-l 3-(Z-methyl-4-oxo2-pentenyD] ethyl xau thate 3 S[2-(2 methyl-4-0Xopentyl)] ethyl xauthate Allyl amyl xanthatc EXAMPLE 24 Flotation of a Copper Ore The product of Example 1 above was tested as a promoter for a second copper ore from the Western United States, using the following procedure. The ore was ground for 6 minutes at 60% solids with 1.5 lb./ton lime to bring the pH to about 7.5, and 0.05 lb./ ton of the compound of Example 1. It was then conditioned for 5 minutes at 22% solids with 0.09 lb./ton of a polypropylene glycol frother. The pulp was floated for 5 minutes, leaving a tailing which analyzed only 0.11% residual copper.

We claim:

1. Compounds of the formulae:

if G wherein R is a member selected from the group consisting of alkyl of one to twelve carbons, and aralkyl, in which the aryl group has not more than two aromatic rings, and

the alkyl group has from one to twelve carbons; and X and a wherein R is a member selected from the group consisting of alkyl of one to twelve carbons, and aralkyl, in which the aryl group has not more than two aromatic rings, and the alkyl groups has from one to twelve carhens; and X and Y are individually selected from the group consisting of hydrogen and halogen,

which comprises reacting a Xanthate of the formula: RO(IIJSM wherein M is an alkali metal and R is as above-defined, with a compound selected from the group consisting of:

wherein X and Y are as above-defined and HALO is a member selected from the group consisting of chloro, brorno and iodo, said reaction being conducted in an inert organic diluent at a temperature in the range of about 10 C. and 40 C.

No references cited. 

1. COMPOUNDS OF THE FORMULAE: 